Question

Two numbers are respectively 30 percent and 40 percent less than a third number. What percent is the second of the first ?

Answer 1

Let the third number = x
$\therefore$ First number = $x-\frac{30x}{100}$
= $\frac{100x-30x}{100}=\frac{70x}{100}=\frac{7x}{10}$
Second number = $x-\frac{40x}{100}$
= $\frac{100x-40x}{100}=\frac{60x}{100}=\frac{6x}{10}$
$\therefore$ Required % = $\frac{\frac{6x}{10}}{\frac{7x}{10}}\times 100$
= $\frac{6x}{10}\times \frac{10}{7x}\times 100=\frac{600}{7}=85\frac{5}{7}$ %